Antenna structure with switching means



April 26, 1 960 M. N LL ET-AL v 2,934,764,

ANTENNA STRUCTURE WITH SWITCHING MEANS Filed April 27, 1956 mvzwrbns: EDWARD NOLL MATTHEW MAND l.

AT TYS.

' Edward M. Noll, Hatboro, and Matthew Mandl, Yardley,

Pa., assignors, by mesne assignments, to Snyder Manufactoring Company, a corporation of Pennsylvania Application April 27, 1956, Serial No. 581,232

a 10 Claims. (Cl. 343-876) The presentinvention relates to a novel antenna struc- United S tes. Patent 2,934,764 Patented Apr. 26,

device showing alternative positions ofthe vertical anture for receiving electromagneticwaves. In particular, t

the present invention relates to an indoor antenna for television receivers having a vertically oriented antenna element. a 7

In commercial television a horizontally polarized signal is broadcast from the transmitter. Because of the horizontal polarization of the broadcast energyfalmost all television receiver antennas are-generally horizontally disposed with respect to the ground. Even those which deviate from the horizontal, such as those indoor types commonly referred to as rabbitears, have a horizontal component of considerable magnitude.

In accordance with the present invention, a oriented antenna element is employed as the primary reception element of the antenna structure. This vertically oriented element is combined with a, generally vertically arranged structure, preferably with a relative small base, and, accordingly, it is less space consuming than an antenna having horizontally projecting portions. Moreover, the novel antenna structure in the course of thorough tests has proved to havesuperior reception properties than presently available antennas. This result has confirmed our theories that the energy received at the home antenna is vertically polarized due to reflection from the ground. In fact, as a consequence of the effect frequently the room in which the antenna is used will have reflecting walls, floors or other surfaces which will produce repolarization of a portion of the vertically polarized magnetic waves into horizontally polarized waves,

and these reflected horizontally polarized waves will not be readily picked-up by the vertically oriented element. Consequently, use of the, antenna of the present invention may eliminate much of the interference normally encountered in television receivers.

In accordance with the present invention, a television antenna having a vertically oriented antenna section capable of serving as a sole antenna element for a television set is provided. In preferred forms of the, invention a vertical antenna section is combined as an element of a structure having, in addition, a folded antenna element and a parallel conductor stub associated with the vertical antenna section. These three elements are preferably connected to three terminals such that the vertical antenna is connected to a first terminal, the parallel conductor stub is connected between the first and a second terminal and the folded antenna element is connected to a third terminal. A selection switch is provided whereby different combinations of these three terminals and the elements connected to them may be connected to another pair of terminals on the frame. To this pair of terminals is connected a two conductor lead which enables connection to a pair of terminals on the television receiver.

vertically tenna element.

Fig. 2 is an elevational view of the device of Fig; 1 a

from the back'with the back cover removed.

Fig. 3 is an electrical circuit diagram schematically representing a possible circuit of the present invention and particularly showing one possible switching arrangement.

Referring first to Figs. 1 and 2 the structure of the present inventionc'onsists of an antenna element 10 which is vertically arranged and mounted on a support structure generally designated 11. The support structure also supports a folded antenna element 12 and a parallel-wire .phasing stub 13.

The support of the present invention is preferably abox 15 on a base 16. The box has a trapazoidal front wall 17, which is preferably a regular tr'apazoid having its major axis vertical. The sidewa'lls of the box .18, 19 are slanted in conformance witlrthe trapezoidal front of the box joined at their tops-to a wall 20 which is shorter than the wall 21 to which they are joined at the bottom. The enclosure may be completed by a removable back cover (not shown). I

The base 16 in this instanceis composed of a pedestal 22 which rests atop a supporting structure, which may be a television set, for example, and a generally U-shaped supporting bracket 23 which rests atop the pedestal and supports the wall 21 of the enclosure 11. a Through the top 20 of the enclosure is provided a conductive support element 25 which has a threaded shank 25a which protrudes vertically downward inside the enclosure through a hole .in the top of the box 20 and a ball receiving socket 256 which remains outside the enclosure and lies against the top 20. Member 25 is held in place ,by portion 25b and a washer 26 on the opposite side of top 20 which washer is held in place by a nut 27 which engages the threaded shank 25a. The antenna section is terminated at its base in a ball 28 which is snugly accommodated within the socket 25b and permits rotation to a slight degree. The antenna element 10 itself is preferably composed of several sections, the bottom-most sec tion 29 of which is preferably tubular and capable of containing telescoped portions of the antenna such as portion 30 which may be capped with a suitable ball 31 or other ornamental and/or protective device. In one typical model of the present invention the antenna elethem 10 was made to have a minimum height of approximately 14 and maximum extension of 50" due to the telescoping effect of several sections. Difierent models of the present invention will of course have different lengths in accordance with the requirements of the particular locality and the requirements of the peculiar conditions under which they are employed.

Protruding through a hole in the front 17 of the enclosure 11 is the rotatable shank of the movable part of a selection switch 3-3. To this shank is attached an appropriate knob 34 which bears a pointer 34a (or another indicator) which enables its adjustment relative to calibrations 35 on the front 17 of the housing 11. The calibrations in accordance with the preferred form of the invention merely indicate positions in which the selection switch is in an operative position. Since the switch 33 is mounted on the housing the various terminals of the switch are supported on the housing. A first terminal 37 is connected by lead 38 to terminal connection member 39 on the shank 25a of vertical antenna section 10. v v The second terminal 40 together with the first terminal 37 provide the terminals to which the leads 41 and 42 of a parallel wire phasing element 13 are connected. A particularly satisfactory wayof obtaining a phasingstuh which has conductors which will remain parallel is to use a section of 300 ohm standard twin lead conductor with polyvinyl insulators 43, although other parallel wire arrangements may be used. The stub is here terminated in a short circuit 44, by twisting the ends of the conductors together. vention an 11-inch shorted section was employed with success. In other embodiments an open ended; section may be employed for a somewhat difiierent effect." The phasing of the stub will, of course, have a somewhat different effect at different frequencies of operation of the television set, but it may be selected of such length and termination that it has an inductive or capacitive effect I over the whole operating broadcast band of the device.

In more complex modifications of the invention the length of the phasing stub. may be modified.

A third terminal 46 is connected by an appropriate lead 47 to the folded antenna element 12. In one particular instance this antenna element was. made 27 inches long and composed of heavy solid wire folded .as shown to. fit an enclosure of the general shape illustrated, In other instances this element might be of diiferen't length and might be folded, in a variety of shapes and patterns and composed of a variety of forms of conductive materials including rod tubing and wire. (either solid or stranded). It is desirable to have vertical sections predominate in this folded element and accordingly vertical sections have been made to predominate in preferred embodiments, as shown.

Connected to another pair of terminals 49 and 50 of the switch are the leads 51, 52 which are included in cord 53 which preferably is 300 ohm twin lead like the phasing stub. This cord passes through the bottom 21 of the enclosure and is terminated in terminals 54, 55, respectively, which are intended to'be attached to the antenna terminals of the television receiver.

It is the purpose of the switch 33 tov permit connection of each of the terminals 495 and 0 to different combinations of the terminals 37, 40, and 46. Fig. 3 shows schematically the circuit diagram. of the antenna, structure of Figs. 1 and 2 and schematically represents the selection switch, This particular switch permits six combinations of antenna terminations. In this particular case the terminals 49, 50 are connected to brushes, 60, 61 which contact conductive rings 62, 63 respectively. The conductive rings 62 and 63 are mounted concentrically on the rotatable switch member 64 which carries contacts 65, 66v connected to the, respective rings so that effectively contact 65 is at the potential of terminal 49 and contact 66 is at the potential of terminal 56. Terminals 37, 40 and 46 are connected to conductors 67, 68, and 69 respectively. Different combinations of these conductors are connected to the switch contact, pairs 70a, 70b, 70c,

70d, 702, and 70), which are positioned to be contacted by moving switch contacts 65, 66.

One contact of pair 7 0a is connected through conductor 69 to folded antenna section 12 and the other contact is connected through conductors 67 and 68 to vertical antenna and phasing stub 13. In the case of contacts 70b one contact is connected to conductors 67. and 69 and the other is connected to conductor 68. In the case of contacts 700 one contact is connected to conductors 68 and 69 and the other contact is connected to conductor 67. In the case of contacts 70d one contact is connected to conductor 69 and the other contact is connected to conductor 67. In the case of contacts 70c one. contact is connected to conductor 67 and the other contact is s same In a particular embodiment of the, in-

connected to conductor 68. In the case of contacts will be connected to one terminal while the phasing stub will be connected to the other. When contacts 70c are contacted, the contact 49 will be connected with the folded antenna and the parallel stub and terminal 50 will be connected with the vertical antenna. When contacts 70d are contacted, the terminal 49 will be connected to the folded antenna elementand-contact 50 will be connected to the vertical antenna, section, When contacts 70a are contacted, terminal. i19-will be connected to the vertical antenna and contact 50 will be connected to the phasing stub. When contacts 70f are contacted, terminal 49 will be connected to the parallel phasing stub and terminal 50 will be connected to the folded antenna.

It will be apparent that additional combinations may be obtained by adding additional contact pairs. The arrangement shown is merely by way of illustration and not intended to imply limitation, although it is a preferred arrangement which has been used in a model of the pres ent invention. It is also possible to have fewer switch positions so that fewer combinations of the antenna structure elements are possible. It is, possible to eliminate elements other than the vertical antenna element and sat stitute elements commonly used in antenna systems.

A preferred embodiment of the present invention has been described. Other modifications of the present invention within the scope of the claims will occur, to those skilled in the art. All such modifications ,are intended to be within the scope and spirit of the present invention.

We. claim: v i

1. An indoor television antenna structure comprising, a supporting frame, a, straight generally vertically extending conductive antenna element supported on the frame, a first terminal supported by the frame and connected to the vertical antenna, a second terminal supported by the frame, a parallel conductor phasing'stub connected between the first and second terminals to provide a phasing elementifor the vertical antenna, a conductive folded antenna element supported on the frame below the vertical antenna, a third terminal supported on the frame and connectedto the folded antenna, a pair of terminals on the frame connectable to a pair of terminals on the receiver, and a selection switch on the frame connecting each terminal of said pair of terminals on the frame to the first, second and third terminals so that a variety of combinations of elements is connectable to the receiver antenna terminals.

2. The antenna structure of claim 1 in which the vertical antenna is adjustable in length.

3'. The" antenna structure of claim 1 in which the frame provides an enclosure within which are housedthe folded antenna, the phasing stub, all terminalsandpart of the selection switch. i

4. -An antenna system comprising a vertically oriented antenna element, a folded antenna element having vertical portions, a parallel conductor phasing stub having one side connected to the vertically oriented element, a twin lead for coupling the system to a'television set and switch means for connecting each of the twin leads to different combinations 'of the vertically oriented antenna element, the folded antenna element and the side of the stub not connected to the antenna element.

5 The structure of claim 1 in which the phasing stub is composed of a section of 300ohrn twin lead transmission line having the ends remote from the first and second terminals shorted.

6. The structure of claim 1 in which the folded antenna section is an elongated rigid metallic. member bent roughly into a spiral form and having predominantly vertical portions.

7. The structure of claim 3 in which the folded antenna section is-formed of flexible wire wound into a generally spiral form and supported by the frame enclosure.

8. The structure of claim 2'in which the generally vertically arranged A tenna. element is composed oftelescoping members which may be moved relative to one another to adjust the length of the structure.

9. An indoor television antenna structure comprising, a supporting frame composed in part of a box-like enclosure, a straight generally vertically extending conductive antenna element supported on the frame top of the enclosure, a selection switch having first, second and third terminals on one side and a pair of terminals on the other, a connection between the first terminal and the vertical antenna element, a parallel conductor phasing stub connected between the first and second terminals to provide a phasing element for the vertical antenna, a conductive folded antenna element of rigid conductive material supported on the frame below the vertical antenna, con nected to the third terminal, and a two conductor lead, each conductor connected to one of the pair of terminals and connectable, in turn, to a pair of terminals on the receiver so that a variety of combinations of elements is connectable to the receiver antenna terminals.

10. The antenna structure of claim 9 in which the terminals are arranged so that in one position of the selection switch one terminal of the pair will be connected to the vertical antenna and the other will be connected to the folded antenna, in another position one terminal is connected to the vertical antenna and the other to the phasing 6 stub, in another position one terminal is connected to the folded antenna and the other to the phasing stub in series with the vertical antenna, in another position one terminal 7 is connected to the folded antenna and the other to the vertical antenna and both terminals of the phasing'stub, in another position one terminal is connected to boththe folded and vertical antenna elements and the other is connected to the other side of the phasing stub, and in still another position one terminal is connected to the folded antenna and to that terminal of the phasing stub remote from the vertical antenna and the other terminal is connected to the vertical antenna.

References Cited in the file of this patent UNITED STATES PATENTS 2,275,324 Brown Mar. 3, 1942 2,509,563 Grashow May 30, 1950 2,636,122 Hayes Apr. 21, 1953 2,710,916 Jones et a1. June 14, 1955 OTHER REFERENCES Antenna Systems Air Force Manual 52-19, June 1953 (pages 117 and 141). 

